Machine tool



M. AHNERT MACHINE TOOL Oct. 21, 1941.

Filed July 29, 1940 2 Sheets-Sheet 1 A ffo rneg Oct. 21, 1941. M. AHN ERT 2,259,870

MACHINE 'TOOL 1 Filed July 29, 1940 2 Sheets-Sheet 2 l QJ j lnven/or Afforneya I Patented Oct. 21, 1941 UNITED STATES PATENT OFFICE MACHINE TOOL .Max Ahnert, vAschersleben, Germany, assignor to Billeter & Klunz, Werkzeugmaschinenfabrik & Eisengiesserei, Aschersleben, Germany Application July '29, 1940, Serial No. 348,229

v In Germany May 125, 1939 Claims. ((151-166) I U My invention relates to a machine tool, more The column I5 is formed by a hollow casting particularly, to a machine of the type in which having a polygonal, preferably a square crossa column mounted on the frame of the machine section. In .itstop wall a bearing [8 is inserted forms a guide for a vertically adjustable cantiand suitably fixed in position. In this bearing lever support on which one or more grinding 5 a shaft I9 is journalled which extends downtools are'mounted for cooperation with the work wardly through the column into the frame caspiece carried by a reciprocatory table. Machines ing I3. of this kind are particularly adapted to accurate- The seat member 14 is formed with a conical 1y finish the guiding faces of frames andtables sleeve 20 in which a tubular post 21 is seated of tool machines or other machines. A machine extending upwardly into the column l5. On this of this kind is disclosed, for instance, in the post the column is rotatably supported by means German Patent No. 355,707. of anti-friction bearings 22 mounted in openings In normal operating condition of the machine of horizontal partition walls of the column I5. the column is firmly clamped to its seat. If it These partition walls are interconnected by vertiis desired to adjust the column in order to swing cal ribs 23-of the column reinforcing the same. the cantilever tool support to a different angular In this manner, a very rigid structure is provided position the clamping means are released and whereby any deflection of the column under the the column is then lifted from its seat. weight of th tools mounted thereon is mini- It is the object of my invention to provide sim- 'mized.

ple means serving the dual purpose of lifting the The column constitutes a vertical guide for a column for this purpose and of raising or lowercantilever tool support 24. Preferably,.this tool ing the cantilever tool support slidable on the support is formed with a cap 25 which surrounds column. the column and is slidably and .non-rotatably Further objects are to provide improved means guided thereon by means of roller bearing elefor rotatably mounting the column on the frame 25 ments 26. These elements are running upon the which will result in a very rigid and compact opposite parallel outer faces of the column. In

structure affording great accuracy in operation; the embodiment shown the cap 25 is integral with to provide means eliminating back-lash in the two cantilever arms 24. Each arm has a horimeans for lifting and lowering the cantilever sup- Zontal guide 21on which one ormore grinding port and to so redesign and combine the various ool ar ie s B ar a j s a y ed, ea

elements of the machine that they can be readgrinding t ol eing driv n y n electric motor ily assembled and disassembled and can be man- 29 attached to the carrier 28.

ufactured at a low price. By turning the column 15 and the cantilever A preferred embodiment of my invention is tool Support 24'mounted thereon about the post illustrated in the accompanying drawings in i, the-Operator may bring one or the other set which of tools 'into' position above the table 12 for op- Fig. 1 is an elevation partly in section along oration-upon a work piece mounted thereon. For

line f Fig, 2; turning'thecolumn I5, the operator must loosen Fig. 2 is a plan view of the machine in which the clamping screws 16 and must then slightly 'the reciprocatory table and the bed thereof is lift the column l5 from the seating member l4 omitted; and to reduce the friction thereon. For this purpose, Fig. 3 is the section taken along the broken the following means are provided: Within the line 33 of Fig. 1. casing 13 a horizontal shaft 30 is mounted which The frame of the machine comprises a base is formed with a cam 3| and has a hand crank plate I 0, a bed H mounted thereon for a recip- 32 for manual'operation. .On rotation of the Irocatory table 2 and a casing I3 mounted on shaft 30 the cam 31 will engage the lower end the base plate lfl adjacent to the bed II and 'acof the shaft I9 and lift the same. As the shaft commodating a plate 14 constituting a .seatfor I9 is secured against axial displacement within a column H5. The plate [4 is rigidly attached the bearing 18 by suitable-co s 3 the column to the casing l3 and thus forms part of the i5 and the cantilever tool support mounted frame structure. It is provided with tappedbores thereon is thus lifted. It may be then swung accommodating screws I6 whereby clamping by hand to the desired position, whereupon the plates I! may be pressed upon a flange of the colclamping crews l6 are tightened again.

umn [5 to firmly clamp the same against the I employthe same shaft 19 for lowering and seating member I 4. lifting th cantilever tool support relative to the zontal shaft 38 which is journalled in the casing- I3 and provided with a hand crank 39. In this manner, the same shaft or spindle l9 may be optionally used to raise or lower the cantilever tool support 24 or to lift the column Hi from its seat M on the frame.

Since the back-lash between the spindle 34 affords a certain freedom of ver-.

tical movement to the cantilever support, the

same could yieldunder excessive pressure'acting upon its tools. It is, therefore, desirable. to provide suitable means for taking up such backlash. 1

For this purpose, I have provided the following means: A plurality of vertical cylinders 40.are

mounted within the casing |3 being circumferentially distributed therein. Plungers 4| guided in these cylinders extend therefrom upwardly through suitable openings in the casing l3 and the seating member l4 and carry rollers bear ing against a lower flange 42 of the cap 25. The bottom of each cylinder 40 is connected with a suitable source of pressure fluid, for instance, with a pump 43. The pressure of this fluid tends to lift the plungers 4| and will thus exert an upward pressure upon the cantilever support.

This pressure exceeds the weight of the latter and will thus take up any back-lash between the nut 35 and the spindle 34. Suitable means are provided to keep the fluid pressure, constant independently of the vertical adjustment of, the cantilever support.

For supplying electric currentto the motors 29, suitable means are provided including slip rings mounted on the post 2| cooperating with brushes diagrammatically indicated at 44. As such means are well known in the art, a detailed explanation thereof appears dispensable.

The location of the shaft the axis of the column, I5 has the advantage that the means for manually operating the spindle .34 raising or lowering the tools may be mounted within the frame. This would not be possible if the spindle 34 were mounted on the outside of the column l5, as itis customary in machines of this kind. Moreover, it will be apparent that the coaxial nested relationship of the elements 25, I5 and 2| results in avery rigid structure ensuring a high accuracy in operation.

While I have described my invention with reference to a specific embodiment thereof, I wish it to be clearly understood that the invention is not limited to the details thereof but is capable of numerous modifications within the scope of the appended claims. 7

WhatI claim is:

l. A machine tool comprising a frame provided with a seat, a column constituting a vertical guide, means for rotatably mounting said column on said seat for angular adjustment thereon, a member slidableon said guide, threaded spinldle journalled in said column and secured against .axial displacement therein, a nut-engaging-said the mite 35 and.

|9 coincidental with r spindle and attached to said member, means for rotating said spindle and means carried by said frame for lifting said spindle, whereby the same' said spindle, and means carried by said frame for lifting said spindle, whereby the same spindle is adapted to raise or lower said cantilever support on said guide or to lift said column from said frame for angular adjustment thereon.

3. A machine tool comprising a frame provided with a seat, a polygonal hollow column rotatably mountedon said seat, a tool support formed with a cap surrounding said column and being slidably and non-rotatably guided thereon, a bearing mounted in the top of said column, a shaft journalled in said bearing and projecting therefrom upwardly and downwardly into said frame, the upwardly projecting end of said shaft constituting a threaded spindle extending through said cap and engaging a threaded bore thereof, a gearing within said frame and adapted to rotate said shaft, and means carried by said frame for lifting said shaft, whereby the same shaft is adapted to raise or lower said tool support on said column or to lift said column from said frame for angular adjustment thereon.

4. A machine tool comprising a frame provided with a seat, a tubular post attached to said frame in the center of said seat, a column rotatably mounted on said post and said seat for angular adjustment thereon, said column constituting a vertical guide, a cantilever tool support slidable on said guide, a threaded spindle journalled in said column and secured against axial displacement therein, a nut engaging said spindle and attached to said cantilever support, means for rotating said spindle and means carried by said frame for lifting said spindle, whereby the same spindle is adapted to raise or lower said cantilever support on said guide or to lift said column from said seat for angular adjustment on said post, 5. A machine tool comprising a frame provided witha seat, a column constituting a vertical guide, means for rotatably mounting saidcolumn on said seat for angular adjustmentthereon, a member slidable on said guide, a threaded spindle journalled in said column and secured against axial displacement therein, a nut engaging said spindle and attached to saidmember, means for rotating said spindle, means carried by said frame for lifting said spindle, whereby the same spindle is adapted to raise or lower said member on said guide or to lift said column from said frame for angular adjustment thereon, vertical cylinders attached to said frame, plungers slidable therein and operable by fluid pressure, and rollers mounted on said plungers and adapted to engage the bottom face of said member to take up the back-lashofthe engagement of said spindle with said nut. Y

4 MAX rman 

